Saturday, 12 March 2011

Genetic engineering is the manipulating of a species’ genetic information so that it produces desirable characteristics.This can be done to trees to improve the quality of the timber they produce, or how they grow. To do this, biologists take DNA from some plants with desirable characteristics and artificially inserting them into another type of tree’s DNA.

Advantages:

Trees can be made to resist disease by being given the traits of other trees that have natural protection to the disease. Additionally, the trees can be given natural defenses to insects. This helps production as tree growth is more efficient and results in more timber.

Trees can be made to grow faster, which has the obvious advantage of the producer being able to grow more trees in the same space of time, therefore making more money.

The forest can be better managed, for example only growing trees of a certain kind, removes the need to deforest areas that are not already replanted trees.

The timber itself can be modified so that once cut from the tree, it resists rot and wear.

Disadvantages:

It is unknown whether or not there are long term side effects of genetic modification.

The modified plants could ‘escape’ and dominate the wild population due to their enhanced characteristics.

The diseases or insects could develop counteractive traits that enhance their effectiveness.

The faster growth could mean that nutrients are not replenished in the soil quickly enough, and more water is needed than is available.

Micro-organisms

Biodegradable polymers are derived from renewable materials that are naturally degradable by micro-organisms. These micro-organisms break the large polymers into smaller less environmentally harmful molecules. As there are large numbers of them naturally occurring in landfill, the polymers will biodegrade if left there.

Biopol and PLA

They are used in packaging, disposables, plastic wrapping, coating paper and board, in agriculture for slow release pesticides, in medecine, pharmaceuticals and textiles.

Advantages

Disadvantages

They are fully degradable in the right conditions.

Semi-biodegradable polymers still remain in the environment for years.

There is a shorter time that rubbish spends in the landfill.

Needs to be sorted from recyclable plastics otherwise their resale value is damaged.

Biodegradable plastics formed from starch use carbon already within our ecosystem, rather than carbon locked up in oil.

They are not widely produced enough for them to benefit from large economies of scale.

Are not as efficient to produce as synthetics such as polypropylene.

The plastics’ degradation can still contribute to global warming due to release of carbon dioxide.